Fingerprint: HIDL: add legacy (2.1) interface definition.

Test: make for bullhead_treble

Change-Id: Ibc720d8cfdd6a3a39904787885ba4f2e398979b3
diff --git a/Android.bp b/Android.bp
index 2ef4e4c..fd56c1c 100644
--- a/Android.bp
+++ b/Android.bp
@@ -4,6 +4,7 @@
     "audio/common/2.0",
     "audio/effect/2.0",
     "benchmarks/msgq/1.0",
+    "biometrics/fingerprint/2.1",
     "graphics/allocator/2.0",
     "graphics/allocator/2.0/default",
     "graphics/mapper/2.0",